1. Field of the Invention
The present invention relates generally to the conversion of carbon dioxide to oxygenates. In another aspect, the invention concerns a catalyst for converting a feed comprising carbon dioxide and hydrogen into methanol and dimethyl ether.
2. Discussion of Prior Art
Carbon dioxide for industrial use is typically recovered from synthesis gas production, substitute-natural gas production, cracking of hydrocarbons, and natural springs or wells. Although carbon dioxide can be used for numerous purposes such as, for example, refrigeration, carbonating beverages, and as an aerosol propellent, in certain situations it may be more desirable to convert carbon dioxide to other higher-value compounds such as oxygenates.
Oxygenates can be used for a variety of purposes such as, for example, enhancing of motor fuel octane and improving the emissions quality of motor fuel. Methanol and dimethyl ether are two oxygenates which can be of particularly high value. Methanol can be used for a variety of purposes including, for example, as an alternative motor fuel, as an intermediate in the production of high octane ethers (e.g., MTBE), and as a fuel for fuel cell driven vehicles. Dimethyl ether is also useful for a variety of purposes including, for example, as an alternative motor fuel, as a starting material towards the synthesis of various hydrocarbons, as a fuel additive to lower emissions, and as an aerosol propellent.
Although it is known that synthesis gas comprising carbon monoxide, carbon dioxide, and hydrogen can be converted into oxygenates using a copper-containing catalyst, there exists a need for a catalyst which is effective to convert carbon dioxide into oxygenates with increased carbon dioxide conversion as well as increased product selectivity towards methanol and dimethyl ether, particularly dimethyl ether.